Study On The Growth Patterns Of Larix Principis-rupprechtii Mary. Plantation In Yanshan Region

The paper selected Larix princips-rupprechtii plantations as study example inYanshan region. Using sample plot survey methods and analytical trees. First, find out thedominant site factors of affect the growth of Larix principis-rupprechtii plantations withquantity theory and then divided the site types. Obtain the growth models of Larixprincipis-rupprechtii plantations under the different site types with growth Curve fittingand then analyzed the growth process.Second, used the predominant factors and controlledother variables, analyzed the influence of a single variable on the dependent variable forstudying the influence of altitude、aspect and soil thickness to Larix princips-rupprechtiiplantations.Finally, on behalf of the regional characteristics of dummy variable isintroduced in the study of growth models to solve the problem of incompatible between thedifferent models in different Regions.And then established the growth models of the largeregional scale.（1）According to the features of northern Yanshan area, we screened out thedominant site factors affectting the growth of Larix principis-rupprechtii plantations,withthe application of quantitative theory Ⅰ. We draw on affecting Index of each site factorson Larix principis-rupprechtii plantations in descending order that altitude> aspect> soilthickness> slope position> gradient. This shows that altitude, aspect and soil thicknesswere the dominant factors which influenced site quality of larix principis-rupprechtiiplantations, while the effects of slope position and gradient were relatively small.According to the principle of combining comprehensive factors and main factor, wedefined that altitude is chosen to divide the site facility, aspect is chosen to divide the sitetype groups, soil thickness is chosen to divide the site type. Finally, The studied forests ofYanshan region have been divided into8site types.（2）The effects of altitude on the growth of DBH and individual volume of larixprincipis-rupprechtii plantations were great and the DBH and individual volume increasedwith the increasing of altitude, but there is little effect on height growth. Slope had agreater impact on the growth of larix principis-rupprechtii plantations, especially30yearslater, average growth of DBH, height and individual volume of larix principis-rupprechtiiplantations in Shady were significantly better than in sunny; Soil thickness had differentdegrees of impact on DBH,height and individual volume. The thicker the soil, the DBH and individual volume increased significantly, but the amount of increase in height growthis not particularly evident.（3）Using common larch plantation growth model, the growth of DBH, tree heightand individual volume of larix principis-rupprechtii plantations for each site type weretested to be merged, and then analyzed the Tree Growth Law according to the growthcurve and we draw a preliminary conclusion about the number mature age of larixprincipis-rupprechtii plantations in this site type.(4) The growth models of DBH, tree height and volume were established based ondummy variable in the three regions.The results showed that the dummy variableSchumacher equation was the best model of the DBH and tree height, the determinationcoefficient R2respectively achieved0.9941,0.9929；residual sum of squares achieved4.7339,6.8849；dummy variable quadratic function was the best model of the volume, withthe determination coefficient R20.9928, the residual sum of squares0.002323. With theindependent test of established models，the results showed that the residuals distributedequality and the accuracy was above95%. It meant that the estimate effect of the modelswere better.